• Journal of Nutrition and Health
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• v.31 no.3
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• pp.253-262
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• 1998

This study was performed to investigated the effect of dietary fat sources on renal senescence in aged rats. Seventeen month old male Sprague-Dawley rats were divided into 3 groups according to urinary protein excretion. Four month old rats were used as a control group. The rats were fed one of three different experimental diets ; 20% beef tallow, 20% corn oil 20% fish oil diet. They were fed experimental diets ad libitum for 16 weeks . The results are summarized as follows. Serum lipid concentrations were higher in aged rats than in control rats, with the beef tallow group showing the highest level, followed by the corn oil and fish oil groups. Old rats showed higher HDL and lower LDL levels than the control groups. Age and dietary fat had no effect on VLDL. GFR for the both age groups were increased with experimental period with the beef tallow group showing the highest value. Urinary protein excretion was also increased with experimental period in both age groups. There was a large increase in urinary protein in old rats that were fed beef tallow and corn oil, but not in old rats fed fish oil. On the contrary , the effect of dietary fat on urinary protein was not found in control groups. There was individual susceptibility in the effect of dietary fat on urinary protein. Old rats fed beef tallow with high initial urinary protein showed highest increase, but , the change was not significant in rats with a low initial value . It was also found that the increase was kept low in rats of the fish oil group with high initial urinary protein. The corn oil group showed in between values. There were no differences in urine and renal tissue concentrations of TXB2 . Aged rats showed a tendency of having higher urinary PGE2 excretion and lower renal cortex content. Since higher PGE2 excretion was reported to be associated with decreased renal function, this might suggest that the aged rats show renal function reduction. Light microscopic examination showed that glomerular segmental sclerosis, mesangial matrix expansion and tubular atrophy were more frequently present in aged rats, and that these changes were more significant in the beef tallow group, followed by corn oil and fish oil groups. The percentage of urinary protein excretion was increased in aged rats in association with increased glomerular sclerosis and mesangial matrix . This change could be partly due to a change in eicosanoids metabolism . Therefore, modification of dietary fat could affect the eicosanoids metabolism in kidney and renal senescence.